Cyclo-oxygenase-2 (COX-2 (PTGS2)), the inducible form of the enzyme, is frequently upregulated in cancer and together with PGE2, is implicated in several aspects of malignant growth including stem cell proliferation, migration, angiogenesis, apoptosis resistance, invasion, and metastasis [31,32,33,34]. Here, PTGS2 is linked to cancer.